Scientists Analyze 2,500-Year-Old Stool Samples of Vikings to Understand DNA of Whipworms That Infect 500 Million People

Scientists are genetically analyzing one of the oldest human parasites, whipworm, from fossilized eggs in 2,500-year-old stool samples from Viking settlements in Copenhagen and Viborg.

The study shows that the global distribution of the whipworm which has developed a complex relationship with humans over thousands of years. Previous studies have revealed that the parasite activates the human immune system and gut microbiome.

Need for Effective Anti-Worm Drugs

Rarely seen in developed countries, the whipworm infects more than 500 million people in developing countries. It has minor negative impact on healthy individuals. Professor Christian Kapel, from UCPH's Department of Plant and Environmental Sciences, said whipworm can lead to serious illness in people who are malnourished or have impaired immune systems. He revealed that their research makes it easier to design more effective anti-worm drugs that can be used to prevent the spread of the parasite in the world's poorest regions.

Vikings (Representational image) Wikimedia commons

The expert said the egg capsules' resistant chitin enabled whipworms' internal DNA to remain well-preserved while the eggs were buried in moist soil. The scientists disembodied the eggs under a microscope, separated them from the stool, and exposed it to genetic analyzes which they had been perfecting for years in earlier investigations.

Ancient Stool Samples

The researchers studied ancient stool samples collected from various locations. They compared these with contemporary samples received from people with whipworms from around the world. As such, the researched gained insight into the evolution of the parasite over ten-thousands of years.

Kapel said the whipworm appears to have spread from Africa to the rest of the world, along with humans about 55,000 years ago following the out of Africa hypothesis on human migration. He explained that during the Viking Age and the Middle Ages, there was no sanitary conditions, or well-separated cooking and toilet facilities, thus good conditions for the whipworm to spread in. The professor said that its very rare today in the industrialized part of the world. But favourable conditions for spreading, unfortunately, still exist in less developed regions.

Researchers believe that whipworm infection can have a beneficial impact on a healthy host. However, in severe infections, it can lead to dysentery, anemia, and rectal prolapsed. Whipworm can impede healthy growth in children.